java操作mysql的帮助类，相当于C#的SqlHelper

java操作mysql的帮助类，相当于C#的SqlHelper

import  java.io.UnsupportedEncodingException;
import  java.sql. * ;
import  java.util.ArrayList;
import  java.util.Hashtable;
import  javax.naming. * ;
import  javax.sql. * ;
import  org.apache.tomcat.dbcp.dbcp.BasicDataSource;

/**
 * <strong>mysql数据库操作帮助类</strong>
 * <p>
 * 包装了mysql常用的操作方法。类似于SqlHelper在java中的实现。
 * </p>
 * 
 *  @author  birdshover
  */
public   abstract   class  mysqlhelper {
     private   static  Boolean locker  =   false ;
     /**
     * 测试使用方法，也可以直接使用，改方法应该只被调用一次。 用来注册数据源。
      */
     public   synchronized   static   void  forTest() {
         if (locker)
             return ;
         else
            locker  =   true ;
        BasicDataSource bdds  =   new  BasicDataSource();
        bdds.setDriverClassName( " org.gjt.mm.mysql.Driver " );
        bdds.setUrl( " jdbc:mysql://localhost:3306/doclight?useUnicode=true&characterEncoding=UTF-8 " );
        bdds.setUsername( " root " );
        bdds.setPassword( " 123 " );
        bdds.setInitialSize( 100 );
        Hashtable env  =   new  Hashtable();
        env.put( " java.naming.factory.initial " ,
                 " org.apache.naming.java.javaURLContextFactory " );
         try  {
            InitialContext ict  =   new  InitialContext(env);
            ict.bind( " MySQL " , bdds);
        }  catch  (Exception ex) {
            locker  =   false ;
            System.out.println(ex.getMessage());
        }
    }

     /**
     * 返回数据库连接对象，连接失败则返回null
     * 
     *  @return  Connection
      */
     private   static  Connection getConnection() {
         try  {
            InitialContext context  =   new  InitialContext();
            DataSource ds  =  (DataSource) context.lookup( " MySQL " );
             return  ds.getConnection();
        }  catch  (NamingException ex) {
             return   null ;
        }  catch  (SQLException ex) {
             return   null ;
        }  catch  (Exception ex) {
             return   null ;
        }
    }

     /**
     * 无结果查询，适用于更新和插入
     * 
     *  @param  SQL语句
     *  @param  语句带的参数
     *  @return  操作影响行数
     *  @throws  SQLException
     * 
     * @example Object[] parms = new Object[2];<br/> parms[0] = "标题"; <br/>
     *          parms[1] = "内容";<br/> int val = mysqlhelper.ExecuteNoneQuery(
     *          "insert into Documents(Title,Content) values (?,?)", parms);
      */
     public   static   int  ExecuteNoneQuery(String cmdtext, Object[] parms)
             throws  SQLException {
        PreparedStatement pstmt  =   null ;
        Connection conn  =   null ;
         try  {
            conn  =  getConnection();
            pstmt  =  conn.prepareStatement(cmdtext);
            prepareCommand(pstmt, parms);
             return  pstmt.executeUpdate();
        }  catch  (Exception ex) {
            System.out.println(ex.getMessage());
        }  finally  {
             if  (pstmt  !=   null ){
                pstmt.clearParameters();
                pstmt.close();
            }
             if  (conn  !=   null )
                conn.close();
            
        }
         return   0 ;
    }

     /**
     * 返回查询结果集
     * 
     *  @param  SQL语句
     *  @param  附带参数
     *  @return  返回结果，用ArrayList包装Object数组
     *  @throws  SQLException
     * 
     * @example ArrayList list =
     *          mysqlhelper.ExecuteReader("Select * from Documents",null); <br/>
     *          for(int i = 0;i&lt;list.size();i++) { <br/> &nbsp;&nbsp;Object[]
     *          obs = (Object[])list.get(i); <br/> &nbsp;&nbsp;for(int j =
     *          0;j&lt;obs.length;j++) { <br/>
     *          &nbsp;&nbsp;&nbsp;&nbsp;out.print(obs[j].toString()); <br/>
     *          &nbsp;&nbsp;} <br/> &nbsp;&nbsp;out.print("&lt;br/&gt;"); <br/>
     *          } <br/>
     * 
      */
     public   static  ArrayList ExecuteReader(String cmdtext, Object[] parms)
             throws  SQLException {
        PreparedStatement pstmt  =   null ;
        Connection conn  =   null ;
        ResultSet rs  =   null ;
         try  {
            conn  =  getConnection();
            pstmt  =  conn.prepareStatement(cmdtext);

            prepareCommand(pstmt, parms);
            rs  =  pstmt.executeQuery();

            ArrayList al  =   new  ArrayList();
            ResultSetMetaData rsmd  =  rs.getMetaData();
             int  column  =  rsmd.getColumnCount();

             while  (rs.next()) {
                Object[] ob  =   new  Object[column];
                 for  ( int  i  =   1 ; i  <=  column; i ++ ) {
                    ob[i  -   1 ]  =  rs.getObject(i);
                }
                al.add(ob);
            }
             return  al;

        }  catch  (Exception ex) {
        }
         finally {
             if  (rs  !=   null )
                rs.close();
             if  (pstmt  !=   null )
                pstmt.close();
             if  (conn  !=   null )
                conn.close();
        }
         return   null ;
    }

     /**
     * 返回第1行第1列数据，一般用来查询count值
     * 
     *  @param  SQL语句
     *  @param  带参数
     *  @return  值
     *  @throws  SQLException
      */
     public   static  Object ExecuteScalar(String cmdtext, Object[] parms)
             throws  SQLException {
        PreparedStatement pstmt  =   null ;
        Connection conn  =   null ;
        ResultSet rs  =   null ;
         try  {
            conn  =  getConnection();

            pstmt  =  conn.prepareStatement(cmdtext);
            prepareCommand(pstmt, parms);

            rs  =  pstmt.executeQuery();
             if  (rs.next()) {
                 return  rs.getObject( 1 );
            }  else  {
                 return   null ;
            }
        }  catch  (Exception e) {
            System.out.println(e.getMessage());
        }  finally  {
             if  (rs  !=   null )
                rs.close();
             if  (pstmt  !=   null )
                pstmt.close();
             if  (conn  !=   null )
                conn.close();
        }
         return   null ;
    }

     private   static   void  prepareCommand(PreparedStatement pstmt, Object[] parms)
             throws  SQLException, UnsupportedEncodingException {
         if  (parms  !=   null   &&  parms.length  >   0 ) {
             for  ( int  i  =   1 ; i  <  parms.length  +   1 ; i ++ ) {
                Object item  =  parms[i  -   1 ];
                String typeName  =  item.getClass().getSimpleName();
                 if  (typeName.equals( " String " )) { 
                    pstmt.setString(i, item.toString());
                }  else   if  (typeName.equals( " Integer " )) {
                    pstmt.setInt(i, Integer.parseInt(item.toString()));
                }  else   if  (typeName.equals( " Date " )) {
                    pstmt.setDate(i, Date.valueOf(item.toString()));
                }  else  {
                    pstmt.setObject(i, item);
                }
            }
        }
    }
}